The solution conformations of natural prostaglandins and analogs are being determined by a combination of circular dichroism, nmr relaxation, and NMR shift reagent studies in aqueous and mixed organic-aqueous media. The results of the conformational studies are compared to activity data in order to determine the stereostructural features essential for biorecognition. Other areas covered by the proposal are the synthesis of polymer tethered prostaglandins and prostaglandin dehydrogenase (PGDH) and evaluation of these materials as assay reagents. BIBLIOGRAPHIC REFERENCES: Molecular Basis for Prostaglandin Potency. I. The Case for Biological Significance of Media Dependent Conformational Changes, E.M.K. Leovey and N.H. Andersen, J. Amer. Chem. Soc., 97, 4148 (1975). Biological Consequences of Prostaglandin Molecular Conformations, N.H. Andersen, P.W. Ramwell, E.M.K. Leovey, and M. Johnson, Adv. Prostaglandin and Thromboxane Research, 1, 271-289 (1976).